The present invention relates to microelectromechanical systems (MEMS) and in particular to MEMS for transferring electrical power while maintaining electrical isolation between the points of transfer.
MEMS are extremely small machines fabricated using integrated circuit techniques or the like. The small size of MEMS makes possible the mass production of high speed, low power, and high reliability mechanisms that could not be realized on a larger scale.
Often in electrical circuits, it is desired to transfer power between two points while maintaining electrical isolation between those points. Isolation, in this context, means that there is no direct current (DC) path between the points of transfer. Isolation may also imply a degree of power limiting that prevents faults on one side of the isolation from affecting circuitry on the other side of the isolation.
Conventional techniques of power transfer with electrical isolation include the use of transformers or capacitors such as may provide alternating current (AC) power transfer while eliminating a direct DC path.
There are drawbacks to these conventional techniques. First, when DC power must be transferred, additional circuitry (chopping) must be used to convert the DC input power to AC to be transferred by the transformer or capacitor. After transfer, further circuitry (rectification) must be used to convert the AC power back to DC power. This additional circuitry adds considerable expense. Second, the volume occupied by the capacitor or transformer may preclude its use in certain applications where many independently isolated circuits must be placed in close proximity or isolation is required-on a very small mechanical scale, for example, on an integrated circuit.